JP3356366B2 - Position adjustment method for solid-state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging device for adjusting a relative position between a solid-state imaging device in an image reading unit such as a facsimile, a copying machine, a scanner, and a lens for forming an optical image on the solid-state imaging device. The present invention relates to an element position adjusting method.

[0002]

2. Description of the Related Art As shown in FIG. 7, an apparatus for reading an optical image using a solid-state image pickup device forms an object 4 on a solid-state image pickup device 2 through an image forming lens 3 and reads the object. The solid-state imaging device 2 includes a one-line solid-state imaging device in which a plurality of minute photoelectric conversion elements (hereinafter, simply referred to as pixels, usually having a size of several μm × several μm) are arranged in a line. Used.

In such an image reading apparatus, the line image formed by the image forming lens 3 is positioned on the solid-state image pickup device 2 and the optical characteristics (focus and magnification) are read with a predetermined required accuracy. The image forming lens 3 and the pixel line 21 of the solid-state imaging device 2 of one line are replaced with x, y,
It is necessary to finely adjust the position in five axes of z, β and γ to adjust the position. A in the figure is the optical axis.

In the above-described adjustment of the relative position between the solid-state imaging device and the imaging lens, measurement of an MTF (modulation transfer function) is used for adjusting the solid-state imaging device in the z-axis direction.
The MTF indicates a change in contrast of a sine wave chart image as a function of a spatial frequency.

[0005] Conventionally, in position adjustment of a solid-state image pickup device, to adjust the position of the solid-state image pickup device in the z-axis direction (optical axis direction), that is, to adjust the focus, "automatic focus adjustment of a television camera by a hill-climbing servo system""(NHK Technology Research
S40, Vol. 17, No. 1, Ishida, Fujimura) is generally used. In this conventional adjustment method, the MTF is measured at several points in the optical axis direction, and a hill-climbing curve of the MTF is calculated based on the measured data to calculate the best focus position.

More recently, in order to read a color image, Red (hereinafter simply referred to as R), Green (hereinafter simply referred to as G), and Blu as shown in FIG.
e (hereinafter simply referred to as B), three lines 1r, 1 in which pixels having a spectral sensitivity peak are arranged in three rows for R, G, and B, respectively.
g, 1b solid-state imaging device 1 is used.

In this case, in addition to the above-described adjustment in the five-axis direction, the degree of freedom with respect to the position of the three-line solid-state imaging device 1 also occurs in the α-direction shown in FIG. Becomes

[0008]

However, since there are a plurality of target lines in the position adjustment of the three-line solid-state imaging device, it takes much time to calculate the hill-climbing curve by measuring the MTF for each line. There was a problem of too much. Therefore, an object of the present invention is to provide a position adjustment method of a solid-state imaging device that can shorten the adjustment time in position adjustment of a three-line solid-state imaging device.

[0009]

According to a first aspect of the present invention, there is provided a method for adjusting a position of a solid-state imaging device, comprising: an imaging lens for converting an object to be read into an optical image; In a solid-state imaging device position adjustment device that adjusts a relative position in the optical axis direction with a solid-state imaging device having color pixel lines based on output information of the solid-state imaging device, the position is measured for each of the three color pixel lines. Comparing the measured MTF value with a preset MTF set value, and moving the solid-state imaging device away from the imaging lens once when the measured MTF value of each color exceeds the set value. Moving toward the imaging lens side, and the MTF values respectively measured corresponding to the red and green pixel lines each exceed the set value, and the blue pixel La Moving the solid-state imaging device toward the image forming lens when the MTF value measured corresponding to the red pixel line is lower than the set value; and measuring the MTF value corresponding to the red pixel line. Exceeds the set value,
Moving the solid-state imaging device toward the imaging lens when the MTF value measured corresponding to the green pixel line is lower than the set value; and measuring the MTF value corresponding to the red pixel line. Moving the solid-state imaging device away from the imaging lens when the measured MTF value falls below the set value and the measured MTF value corresponding to the green pixel line exceeds the set value. And the MTF values respectively measured for the red and green pixel lines are below the set values, and the MTF values measured for the blue pixel lines are above the set values. Moving the solid-state imaging device in a direction away from the imaging lens, and when the measured MTF values corresponding to the red, green, and blue pixel lines are all below the set value. On, solid shooting After moving in a direction away from the once imaging lens elements, characterized by comprising the step of moving toward the solid-state imaging device in the imaging lens side, respectively.

According to a second aspect of the present invention, there is provided a method for adjusting the position of a solid-state image sensor, comprising: an imaging lens for converting an object to be read into an optical image; and a pixel line of three colors of red, green and blue for photoelectrically converting the optical image. In the position adjustment device of the solid-state imaging device that adjusts the relative position in the optical axis direction with the solid-state imaging device based on the output information of the solid-state imaging device, the MTF value measured for each of the three color pixel lines and Comparing the MTF set values corresponding to the preset pixel lines of each color with the solid-state imaging device once when the measured MTF values of the respective colors exceed the corresponding set values, respectively; Moving toward the direction away from the lens, and then moving toward the imaging lens; and measuring the MT measured corresponding to the red and green pixel lines, respectively.
When the F value exceeds the corresponding set value and the MTF value measured corresponding to the blue pixel line is lower than the corresponding set value, the solid-state imaging device is turned to the imaging lens side. Moving and the MTF value measured for the red pixel line is above its corresponding set value and the MTF value measured for the green pixel line is below its corresponding set value. Moving the solid-state imaging device toward the imaging lens side, the MTF value measured corresponding to the red pixel line falls below the corresponding set value, and corresponds to the green pixel line. Measured MTF
Moving the solid-state imaging device in a direction away from the imaging lens when the value exceeds the corresponding set value; and measuring the MTF values corresponding to the red and green pixel lines respectively. If the MTF value corresponding to the blue pixel line is below the corresponding set value and exceeds the corresponding set value, the solid-state imaging device is moved in a direction away from the imaging lens. Process and
When the MTF values measured for the red, green, and blue pixel lines are respectively below the corresponding set values, the solid-state imaging device is temporarily moved in a direction away from the imaging lens, Moving the image sensor toward the imaging lens.

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

In the position adjusting method for a solid-state image pickup device according to the present invention, the MTF value measured for each of the three color pixel lines is compared with a preset MTF set value, and the comparison result is obtained. Since the moving direction of the solid-state imaging device is determined based on the above, there is no need to calculate the “hill-climbing curve” of the MTF, and the adjustment time can be significantly reduced.

In the method for adjusting the position of a solid-state imaging device according to the present invention, the MTF value measured for each of the three color pixel lines and the MTF set value corresponding to each of the previously set pixel lines are determined. Are compared, it is possible to set a different MTF set value for each color.

[0021]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIGS. FIG. 1 is a flowchart showing an outline of a control flow of a control unit including the embodiment,
FIG. 2 is a block diagram of the position adjusting device controlled by the control flow of FIG. 1, and FIG. 3 is an exploded perspective view of the image reading device whose position is adjusted.

As shown in FIG. 3, a solid-state image sensor (hereinafter, referred to as a solid-state image sensor)
It is called CCD. 1) is soldered to a solid-state image sensor substrate 5, and the solid-state image sensor substrate 5 is fixed to a solid-state image sensor holding member 6 with screws 7. At this time, a spring washer 8 and a flat washer 9 are fitted to the screw 7.

As the solid-state image sensor holding member 6, a member having higher rigidity than the solid-state image sensor substrate 5 is used, and when the position adjusting device described later is chucked by the position adjusting device, the solid-state image sensor holding member 6 is hardly distorted. It has become.

The solid-state image sensor holding member 6 is fixed to the solid-state image sensor fixing member 10 with an adhesive after the position adjustment described later is completed, that is, after the position adjustment between the CCD 1 and the imaging lens 3 is completed. . Specifically, the projection 1 of the solid-state image sensor fixing member 7 is inserted into the hole 18 of the solid-state image sensor holding member 6.
9 is inserted, and an adhesive is applied and fixed between the hole 18 and the protrusion 19. In addition, although there are three bonding portions here, the number is not limited as long as it is one or more.

Further, the solid-state image pickup device fixing member 10 on the side of the imaging lens 3 to which the solid-state image pickup device holding member 6 on the CCD 1 side is fixed after positioning, has a V-block portion 11, and this portion is formed. The image lens 3 is placed, a leaf spring 12 for lens pressing is arranged from above, and the image lens 3 is fixed by tightening a screw 13.

The solid-state image pickup device fixing member 10 is fixed to the main body mounting member 17 through a flat washer 14 and a spring washer 15 and a screw 16 through a screw hole 51 for fixing a lens. Further, the body mounting member 17 is fixed to an image reading apparatus body (not shown). The lens fixing screw hole 51 is formed in a vertically long hole so that the position of the imaging lens 3 can be adjusted in the optical axis direction (z direction).

Further, when the position of the imaging lens 3 is adjusted, the solid-state imaging device fixing member 10 has a lens position adjusting pin 24 provided on the image reading device supporting member 21 side (see FIG. 3). Is provided with a pin hole 52 for adjusting the lens position into which is inserted.

Next, the configuration of the position adjusting device will be described in accordance with the position adjusting procedure of the CCD 1 and the imaging lens 3. First, the imaging lens 3 is fixed to the solid-state imaging element fixing member 10 with the screw 13 via the lens pressing leaf spring 12. Further, in this state, the flat washer 14, the spring washer 15
And is fixed by screws 16.

Next, in this assembled state, it is mounted on the position adjusting device shown in FIG. This position adjusting device is a surface plate 2
An image reading device support member 21 and a light source chart support member 22 are disposed on the light source chart support member 22, and a chart glass 30, a light source 31, and a light source reflector 32
Is installed.

On the surface of the chart glass 30, a chart capable of detecting optical characteristics, specifically, focus, magnification, deviation of the optical axis, and the like is formed.
And the direct light from the light source 31 and the light source reflector 32
And the reflected light from the chart glass 30.

Therefore, by attaching the above-mentioned assembling member to the image reading device support member 21, a chart image is formed on the CCD 1 via the imaging lens 3.

The solid-state image pickup device substrate 5 to which the CCD 1 is fixed is fixed to a solid-state image pickup device holding member 6 with screws, and the solid-state image pickup device holding member 6 is held by a solid-state image pickup device chuck section 43. Further, the solid-state image pickup device chuck section 43 is provided with a stage and an actuator (not shown) which are means movable in six axes of x, y, z, α, β, and γ.

Further, since the solid-state image pickup device holding member 6 is formed of a member having higher rigidity than the solid-state image pickup device substrate 5, even if it is gripped by the solid-state image pickup device chuck portion 43, distortion does not easily occur. The influence on the solid-state imaging device substrate 5 is extremely small as compared with the case where the user directly grips the reference numeral 5.

The solid-state image sensor fixing member 10 fixing the imaging lens 3 is a solid-state image sensor fixing member chuck 2 having an actuator as a moving means in the direction of the optical axis A.
3. Further, the main body mounting member 17 is mounted on the image reading device support member 21 side. Therefore, the chart image is photoelectrically converted by the CCD 1 and the data is used to calculate the optical characteristics such as focus, magnification, tilt of the optical axis, etc. The above-described solid-state imaging device chuck unit 4
The position adjustment is performed by moving the chuck member 23 and the solid-state imaging element fixing member 23.

The movement amount control circuit 40 for controlling the position adjustment is constituted by a microcomputer including a RAM, a ROM, an I / O port and the like (not shown), and will be described later based on a control program stored in the ROM. Control of each section as described above. This movement amount control circuit 40 includes a CC
The output data of the CCD 1 is input via a CCD output data calculation circuit 44 for calculating the output data of D 1 and a CCD drive circuit 45 for driving the CCD 1.

Further, the movement amount control circuit 40 includes:
The solid-state image sensor fixing member chuck 23 that moves the imaging lens 3 in the optical axis direction (z-direction) is connected via a lens-side moving stage driving unit 41 and via a CCD-side moving stage driving unit 42. , The solid-state imaging device chuck unit 43 is connected.

Next, a position adjusting method including the present embodiment will be described based on the control flow of FIG. In the work setting process of step S1, three pixel lines 1r, 1g,
The solid-state imaging device holding member 6 to which the CCD 1 having the CCD 1b is fixed via the solid-state imaging device substrate 5 is gripped by the solid-state imaging device chuck portion 43, and the solid-state imaging device fixing member 10 to which the imaging lens 3 is fixed. Is held by the solid-state image sensor fixing member chuck 23.

In the optimal CCD initial position setting step of step S2, the CCD 1 is set to the initial position using the position data stored in the final adjustment position of step S17. That is,
The amount of movement of the CCD 1 for setting the initial position moves with reference to the final position of the previous work whose position has been adjusted.

In the CCD output confirmation step of step S3,
The CC corresponding to the center line (G line in this embodiment) 1g of the three pixel lines 1r, 1g, 1b of the CCD 1
Whether the output of D1 is present or not is determined by the CC of the CCD drive circuit 45.
Confirm by D output detection means. If the work is not confirmed, the work is regarded as defective and the process proceeds to step S18, where it is determined whether or not the next work is set. If the next work is not set, the process is terminated. When the next work is set, the process returns to step S1.

In the lens adjusting mechanism setting step of step S4, the imaging lens 3 is movable back and forth in the Y-axis direction and
The lens position adjusting pin 24, which is rotatably supported in one direction, is inserted into the lens position adjusting pin hole 52. Further, the lens fixing screw tightening bit 25 supported on the image reading device supporting member 21 side so as to be movable forward and backward in the Y axis direction and rotatable in both forward and reverse directions is inserted into the lens fixing screw hole 51, and the screw tightening bit is inserted. 25 is screwed into the screw 16. Then, the imaging lens 3 and the solid-state imaging device fixing member 1
0 is temporarily fixed to the body mounting member 17.

In the CCD first position adjustment step of step S5, the solid-state image sensor holding member 6, which is held by the solid-state image sensor chuck portion 43 by means movable in six axial directions,
The solid-state imaging device substrate 5 and the CCD 1 are moved integrally, and the CCD 1 is rotated in two directions of x, y, γ, and β in two directions.
The first position adjustment is performed. That is, the CCD 1 is directly opposed to the imaging lens 3. Also in this position adjustment, since the adjustment of the biaxial rotation in two directions is a target, the adjustment can be performed only with the central G line 1g.

In the lens fixing screw loosening step of step S6, the bit 25 is turned to rotate the screw 16 on the imaging lens 3 side in order to adjust the lens position by one-direction uniaxial rotation (z, β).
Loosen.

In the second position adjustment step of the CCD 1 in step S7, the solid-state image sensor holding member 6, the solid-state image sensor substrate 5, and the CCD 1 held by the solid-state image sensor chuck portion 43 by means movable in six axial directions are moved. By moving integrally, the second position adjustment of the CCD 1 in the y direction is performed.

In the lens position adjusting step of step S8,
The lens-side moving stage driving section 41 drives the moving means in the optical axis direction of the solid-state image sensor fixing member chuck section 23 to adjust the position of the imaging lens 3 in the z direction to adjust the magnification.

In the CCD position temporary adjustment step of step S9, the moving means of the solid-state image pickup device chuck unit 43 is driven by the CCD-side moving stage drive unit 42, and the CC in the z direction is driven.
The temporary adjustment of the focus is performed by performing the temporary adjustment of the D position.

In the lens rotation adjustment step of step S10, the rotation of the imaging lens 3 on the β axis is adjusted using the MTF chart so that the difference between the MTFs at the left and right ends of each line falls within a specified range.

In the determination step of step S11, it is determined whether or not the difference between the MTFs at the left and right ends of each line is within a specified range. If not, the process returns to step S5. If it is within the standard range, the process proceeds to step S12.

In the lens fixing step of step S12, the imaging lens 3 is fixed by tightening the screw 16 by rotating the bit 25. Thus, the position adjustment of the imaging lens 3 ends. In the lens fixing mechanism retreating step of step S13, the moving pin 24 and the screw tightening bit 25 for adjusting and fixing the lens position are pulled out.

After the position adjustment of the imaging lens 3 is completed as described above, the final position adjustment of the CCD 1 is performed.
That is, in the third position adjustment step of the CCD 1 in step S14, the actuator of the CCD chuck section 43 is driven by the CCD-side moving stage drive section 42 so that x, y, γ,
The position of the CCD in biaxial rotation in two directions β is adjusted.

In the main adjustment process of the CCD 1 in step S15, the actuator of the CCD chuck unit 43 is driven by the CCD-side moving stage drive unit 42 to move the CC in the z direction.
Perform D-position main adjustment.

In the determination step of step S16, it is determined using the MTF chart whether the difference between the MTFs at the left and right ends of each line is within a standard range. If it is out of the standard range, the process returns to step S14. If it is out of the standard range, the adjustment is completed and the process proceeds to step S17.

In the final adjustment position storage step of step S17, the final adjustment positions of the CCD 1 and the imaging lens 3 obtained as described above are stored, and the stored final adjustment position information is stored in the initial position of step S2. This is fed back to the setting process and used as position information for setting the initial position of the next work.

In step S18, it is determined whether the next work is set. If the next work is to be set, the process returns to step S1; otherwise, the process ends. The determination as to whether or not to set the next work is performed by, for example, setting the number of works to be position-adjusted in advance, and comparing the set number with the counted final adjustment completed number.

Next, in the method for adjusting the position of the solid-state image pickup device, the CCD main adjustment process in the z direction performed in step S15 according to the present embodiment will be described below. FIG. 4 shows C
FIG. 4 is a block diagram of a CCD main adjustment device for performing a main adjustment in the z direction of the CD.

As shown in FIG. 4, the CCD main adjustment device is
Chart glass 35 with MTF chart formed on the surface
A CCD drive circuit 45 for driving the CCD 1 disposed at the image position of the imaging lens 3, a CCD output data calculation circuit 44 for calculating output data of the CCD 1 and inputting the output data of the CCD 1 to the movement amount control circuit 40. And a CCD z-axis driving unit 60 that drives the CCD 1 in the z-axis direction in accordance with the output from the movement amount control circuit 40. This CCD
The z-axis drive unit 60 is included in the CCD-side moving stage drive unit 42 and the CCD chuck unit 43 in FIG.

The CCD output data operation circuit 44 includes a CCD
An MTF calculation / comparison circuit 44a for calculating an MTF based on an output from the drive circuit 45 and performing a comparison operation;
An adjustment movement direction determination circuit 44b for determining the movement direction (direction) in the axial direction is provided.

The movement amount control circuit 40 includes a CCD output data calculation circuit 44 for calculating the output data of the CCD 1 and C
The CCD1 is driven via a CCD drive circuit 45 for driving the CD1.
Is configured to be input.

Next, the operation of the main CCD adjusting apparatus in this embodiment will be described with reference to FIGS. FIG. 5 is a flowchart showing an outline of a control flow of the control unit of the present embodiment, and FIG. 6 is a diagram showing a tendency of an MTF curve corresponding to each pixel line. In FIG. 6, the horizontal direction is the z-axis direction (the left direction is the z-axis + direction, ie, the direction approaching the imaging lens, and the right direction is the z-axis-direction, ie, the direction moving away from the imaging lens), and the vertical direction is the MTF value. MTF curve 73 corresponding to B pixel line 1b, MTF curve 72 corresponding to G pixel line 1g, and MT corresponding to R pixel line 1r.
An F-curve 71 is shown. Further, an MTF threshold level L which is a preset MTF set value is shown. Then, the pixel lines 1r, 1g, 1b of each color
The MTF threshold level L of the region M1, the region M1, the region M
2, the area M3, the area M4, the area M5, and the area M6. Note that FIG. 16 shows whether the MTF curve in each area exceeds the threshold level.
Each curve pattern is shown. In FIG. 16, when exceeding, Δ is displayed when not exceeding.

An area M1 indicates a range where all of the MTF curves 71 to 73 corresponding to the respective colors of R, G and B exceed the MTF threshold level L. The region M2 is a region where the MTF curves 71 and 72 corresponding to R and G both exceed the MTF threshold level L.
Is the MTF threshold level L
It shows the range of the part excluding the part exceeding. The region M3 is a portion of the portion where the MTF curve 71 corresponding to R exceeds the MTF threshold level L excluding a portion where the MTF curve 73 or 72 corresponding to B or G exceeds the MTF threshold level L. The range is shown.

The area M4 has M and M corresponding to B and G, respectively.
Of the portions where the TF curves 73 and 72 both exceed the MTF threshold level L, the MTF curve 71 corresponding to R is M
The range of the portion excluding the portion exceeding the TF threshold level L is shown. The area M5 is the MTF corresponding to B
The curve 73 shows the range of the portion exceeding the MTF threshold level L excluding the portion where the MTF curve 72 or 71 corresponding to G or R exceeds the MTF threshold level L. An area M6 indicates a range of a portion exceeding the MTF threshold level L, in which no portion exceeding the MTF threshold level L of the MTF curves 71 to 73 corresponding to each of R, G, and B exists. .

In this CCD main adjustment, the CTF is adjusted so that all of the MTF values corresponding to the pixel lines 1r, 1g, and 1b of each color exceed the preset MTF threshold level L.
Adjust the position of CD1 in the z-axis direction.

As shown in FIG. 5, in the subroutine of the main CCD adjustment process in the z-axis direction in step S15, first, in step S19, an MTF threshold level L common to each of the R, G, and B colors is set.

Next, in step S20, each pixel line 1r, 1g, 1c of the CCD 1 at the adjustment start position in this step.
An MTF value corresponding to each of R, G, and B colors is obtained from the output of b. Next, in step S21, it is determined whether the MTF value of the R pixel line 1r exceeds the MTF threshold level L set in step S19. If the MTF value of the R pixel line 1r does not exceed the MTF threshold level L, the process proceeds to step S22.

In step S22, G pixel line 1g
Is determined to exceed the MTF threshold level L set in step S19. G
If the MTF value of the pixel line 1g does not exceed the MTF threshold level L, the process proceeds to step S23.

In step S23, the B pixel line 1b
Is determined to exceed the MTF threshold level L set in step S19. B
If the MTF value in the pixel line 1b does not exceed the MTF threshold level L, the process proceeds to step S24.

In step S24, the block including the CCD 1 is moved in the z-axis direction (direction approaching the imaging lens 3) at an arbitrary moving amount (fine pitch) and searched. Then, in the next step S32, the MTF is measured based on the movement search in step S24, and all the MTF values corresponding to the respective colors of R, G, and B are set in the step S19.
A range (region) M1 exceeding the F threshold level L is determined.

Then, in step S33, step S
The block including the CCD1 is moved to the center of the area M1 determined in 32. In step S23, the pixel line 1b of B
Is greater than the MTF threshold level L set in step S19, the process proceeds to step S2.
Go to 5.

In step S25, the block including the CCD 1 is moved in the z-axis direction (direction moving away from the imaging lens 3) at an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 and the above-described step S32
And the process of step S33 is performed. G in step S22
If the MTF value of the pixel line 1g exceeds the MTF threshold level L set in step S19, the process proceeds to step S26. In this case, in this embodiment, as shown in FIG. 6, the MTF value of the B pixel line 1b also exceeds the MTF threshold level L.

In step S26, the block including the CCD 1 is moved in the z-axis direction (direction moving away from the imaging lens 3) at an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 and the above-described step S32
And the process of step S33 is performed. R in step S21
If the MTF value of the pixel line 1r exceeds the MTF threshold level L set in step S19, the process proceeds to step S27.

In step S27, the G pixel line 1g
Is determined to exceed the MTF threshold level L set in step S19. G
If the MTF value of the pixel line 1g does not exceed the MTF threshold level L, the process proceeds to step S28. In this case, in this embodiment, as shown in FIG. 6, the MTF value of the B pixel line 1b does not exceed the MTF threshold level L.

In step S28, the block including the CCD 1 is moved in the z-axis + direction (the direction approaching the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 to perform the processes of steps S32 and S33 described above.

If it is determined in step S27 that the MTF value of the G pixel line 1g exceeds the MTF threshold level L, the flow advances to step S29. In step S29, the MTF value of the B pixel line 1b is set in step S29.
It is determined whether or not the MTF threshold level L set at 19 is exceeded. MT in B pixel line 1b
If the F value does not exceed the MTF threshold level L, the process proceeds to step S30.

In step S30, the block including the CCD 1 is moved in the z-axis + direction (the direction approaching the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 to perform the processes of steps S32 and S33 described above. If the MTF value of the B pixel line 1b exceeds the MTF threshold level L set in step S19 in step S29, the process proceeds to step S31.

In step S31, after moving and searching in the negative direction of the z axis, a search is made to move in the positive direction of the z axis from the survey start position. Then, the process proceeds to step S32 and the above-described step S32
And the process of step S33 is performed. Step S3
The search for movement in the z-axis direction in 1 is performed until one boundary of the area M1 is determined in step S32, and after one boundary is determined, the movement search is performed in the z-axis + direction. As described above, the MTF value corresponding to each color is set to the preset M
By monitoring and determining whether or not the TF threshold level L has been exceeded, the moving direction of the block CCD can be determined.

In the above embodiment, the processing is performed when the coarse adjustment of the CCD 1 has already been completed and the output from the CCD 1 is obtained. However, when the coarse adjustment of the CCD 1 is omitted, as shown in FIG. In step S24 'instead of step 24 in FIG. 5, after moving in the z-axis direction by a fixed amount, z
Search by moving in the axis + direction.

In the above embodiment, a value common to each of the R, G, and B colors is set as the MTF threshold level L. However, in step S19, a different MT value is set for each of R, G, and B.
F threshold levels L _R , L _G , and L _B are set, and the MTF threshold levels L _R ,
L _G, of L _B, step S21, S22, S23, S
27, the determination may be made using the MTF threshold level of the color corresponding to the color of the pixel line to be compared in S29. In this case, in step S32, when the area is determined, the area is determined to be an overlapping part exceeding the MTF threshold levels L _R , L _G , and L _B for each of the R, G, and B colors.
By setting different MTF threshold levels L _R , L _G , and L _B for each of R, G, and B in this manner, the wavelength (color)
The MTF threshold level L can be adjusted according to the difference in the sensitivity of the photoconductor due to the above. In the above embodiment, the block CC is set at the center of the area M1 in step S33.
Although D is moved, it does not have to be the center as long as it is within the area M1.

Next, the operation of the main CCD adjusting apparatus according to another embodiment will be described with reference to FIGS. FIG.
1 is a flowchart showing the outline of the control flow of the control unit of the present embodiment, and FIG. 12 shows the M corresponding to each pixel line.
It is a figure which shows the tendency of a TF curve. In FIG. 12, the horizontal direction is z.
The axial direction (the left direction indicates the z-axis + direction, that is, the direction approaching the imaging lens, and the right direction indicates the z-axis-direction, that is, the direction moving away from the imaging lens), and the vertical direction is the MTF value, and the B pixel line 1b MTF curve 273 corresponding to pixel line 1 of G
MTF curve 272 corresponding to g and pixel line 1r of R
Is shown as the MTF curve 271 corresponding to. further,
An MTF threshold level L which is a preset MTF set value is shown. The portions of the pixel lines 1r, 1g, and 1b of each color that exceed the MTF threshold level L depend on the degree of overlap of the MTF curves 271 to 273, so that the areas M1, M2, M3, M5, and M
6, divided into areas M7.

An area M1 indicates a range where all of the MTF curves 271 to 273 corresponding to the respective colors of R, G and B exceed the MTF threshold level L.
The region M2 includes MTF curves 271, 2 corresponding to R and G.
Numeral 72 indicates the range of the portion exceeding the MTF threshold level L excluding the portion where the MTF curve 273 corresponding to B exceeds the MTF threshold level L. The area M3 is a region where the MTF curve 271 corresponding to R exceeds the MTF threshold level L
Or the MTF curve 273 or 272 corresponding to G
The range of the portion excluding the portion exceeding the threshold level L is shown.

The area M7 is the area corresponding to M corresponding to B and R.
The MTF curve 27 corresponding to G in the portion where both the TF curves 273 and 271 exceed the MTF threshold level L
2 indicates the range of the portion excluding the portion exceeding the MTF threshold level L. In the area M5, in the portion where the MTF curve 273 corresponding to B exceeds the MTF threshold level L, the MTF curve 272 corresponding to R
The range of the portion excluding the portion exceeding the F threshold level L is shown. The region M6 indicates a range of portions where the MTF threshold level L is exceeded and where there is no portion exceeding the MTF threshold level L of the MTF curves 271 to 273 corresponding to the R, G, and B colors. .

In this CCD main adjustment, the CTFs are set so that all of the MTF values corresponding to the pixel lines 1r, 1g, and 1b of each color exceed the preset MTF threshold level L.
Adjust the position of CD1 in the z-axis direction.

As shown in FIG. 11, z in step S15
In the subroutine of the axial CCD main adjustment process,
First, in step S219, an MT common to each of the R, G, and B colors is set.
Set the F threshold level L.

Next, in step S220, each pixel line 1r, 1g,
An MTF value corresponding to each of R, G, and B colors is obtained from the output of 1b. Next, in step S221, it is determined whether the MTF value of the R pixel line 1r exceeds the MTF threshold level L set in step S219. R
If the MTF value of the pixel line 1r does not exceed the MTF threshold level L, the process proceeds to step S222.

In step S222, G pixel line 1
g is the MT value set in step S219.
It is determined whether or not the F threshold level L has been exceeded. If the MTF value in the G pixel line 1g does not exceed the MTF threshold level L, step S2
Proceed to 23.

In step S223, the pixel line 1 of B is
b is the MT value set in step S219.
It is determined whether or not the F threshold level L has been exceeded. If the MTF value in the B pixel line 1b does not exceed the MTF threshold level L, step S2
Proceed to 24.

In step S224, after moving by a fixed amount in the z-axis direction, a search is made in the z-axis direction. Then, in the next step S233, the MTF is measured based on the movement search in step S224, and the MTF corresponding to each of the R, G, and B colors is measured.
A range (region) M1 in which all of the TF values exceed the MTF threshold level L set in step S219 is determined.

Then, in step S233, the block including the CCD 1 is moved to the center of the area M1 determined in step S232. If the MTF value of the B pixel line 1b exceeds the MTF threshold level L set in step S219 in step S223, the process proceeds to step S225.

In step S225, the block including the CCD 1 is moved in the z-axis direction (direction moving away from the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched.
Then, the process proceeds to step S233, and the process proceeds to step S233.
233 and step S234. Step S
If the MTF value of the G pixel line 1g at 222 exceeds the MTF threshold level L set in step S219, the process proceeds to step S226.

In step S226, a block including the CCD 1 is moved in the z-axis direction (a direction away from the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched.
Then, the process proceeds to step S233, and the process proceeds to step S233.
233 and step S234. Step S
If the MTF value of the R pixel line 1r at 221 exceeds the MTF threshold level L set at step S219, the process proceeds to step S227.

In step S227, the G pixel line 1
g is the MT value set in step S219.
It is determined whether or not the F threshold level L has been exceeded. If the MTF value in the G pixel line 1g does not exceed the MTF threshold level L, step S2
Proceed to 28. In step S228, the pixel line 1 of B
b is the MT value set in step S219.
It is determined whether or not the F threshold level L has been exceeded. If the MTF value of the B pixel line 1b has exceeded the MTF threshold level L, the process proceeds to step S226, and the process of step S226 described above is performed. If the MTF value of the b-th pixel line 1b does not exceed the MTF threshold level L, the process proceeds to step S229.

In step S229, the block including the CCD 1 is moved in the z-axis + direction (direction approaching the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S233 and proceeds to step S23 described above.
3 and the processing of step S234.

In step S227, the G pixel line 1g
If the MTF value at the time exceeds the MTF threshold level L, the process proceeds to step S230. Step S2
At 30, it is determined whether the MTF value of the B pixel line 1b exceeds the MTF threshold level L set at step S219. If the MTF value in the B pixel line 1b does not exceed the MTF threshold level L, the process proceeds to step S231.

In step S231, the block including the CCD 1 is moved in the z-axis + direction (direction approaching the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S233 and proceeds to step S23 described above.
3 and the processing of step S234. Step S23
0 and the MTF value of the B pixel line 1b is
If it exceeds the MTF threshold level L set in 219, the process proceeds to step S232.

In step S232, after moving and searching in the negative direction of the z axis, a search is made to move in the positive direction of the z axis from the survey start position.
Then, the process proceeds to step S233, and the process proceeds to step S233.
233 and step S234. The movement search in the z-axis direction in step S232 is performed in the area M1.
Are performed until one boundary is determined in step S233. After the one boundary is determined, the moving search is performed in the z-axis + direction. As described above, the moving direction of the block CCD can be determined by monitoring and determining whether the MTF value corresponding to each color has exceeded the preset MTF threshold level L.

In the above embodiment, the case where the coarse adjustment of the CCD 1 is omitted and the processing is performed when the output from the CCD 1 cannot be obtained. However, since the coarse adjustment of the CCD 1 has already been completed, the output from the CCD 1 is not output. If it is obtained, as in the embodiment of FIG. 5, in step S224, the block including the CCD 1 is moved in the z-axis + direction (the direction approaching the imaging lens 3) at an arbitrary movement amount (fine pitch). Search.

In the above embodiment, a value common to the R, G, and B colors is set as the MTF threshold level L. However, in step S219, a different MT value is set for each of R, G, and B.
F threshold levels L _R , L _G , and L _B are set, and the MTF threshold levels L _R ,
L _G, of L _B, step S221, S222, S22
3, the determination may be made using the MTF threshold level of the color corresponding to the color of the pixel line to be compared in S227, S228, and S230. In this case, step S
At 233, when determining an area, the MT for each of R, G, and B colors
The overlapped portion exceeds the F threshold levels L _R , L _G , and L _B. Thus, different M for each of R, G, B
TF threshold level L _R, L _G, by setting the L _B, it is possible to adjust the MTF threshold level L in accordance with the difference in sensitivity of the photosensitive member due to the wavelength (color). In the above embodiment, the area M1 is determined in step S234.
The block CCD is moved to the center of the area M1.
It does not have to be the center if it is inside.

Next, the operation of the main CCD adjustment apparatus according to another embodiment will be described with reference to FIGS. FIG.
3 is a diagram showing a tendency of an MTF curve corresponding to each pixel line. In FIG. 13, the horizontal direction is the z-axis direction (the left direction is the z-axis +
Direction, ie, the direction approaching the imaging lens, the right direction indicates the z-axis direction, ie, the direction moving away from the imaging lens), the vertical direction is the MTF value, and the MTF corresponding to the B pixel line 1b
Curve 373, MTF curve 372 corresponding to G pixel line 1g, and MTF curve 3 corresponding to R pixel line 1r
71 is shown. Further, a preset MT
The MTF threshold level L which is the F set value is shown. Then, the MT of the pixel lines 1r, 1g, and 1b of each color is
The portion exceeding the F threshold level L is the MTF curve 371.
The region M1, the region M2,
The area is divided into an area M3, an area M4, an area M6, and an area M8.

An area M1 indicates a range where all of the MTF curves 371 to 373 corresponding to the respective colors of R, G, and B exceed the MTF threshold level L.
The region M2 includes MTF curves 371, 3 corresponding to R and G.
Numeral 72 indicates a range of a portion excluding the portion where the MTF curve 373 corresponding to B exceeds the MTF threshold level L among the portions exceeding the MTF threshold level L. The region M3 is a region where the MTF curve 371 corresponding to R exceeds the MTF threshold level L
Or, the MTF curve 373 or 372 corresponding to G
The range of the portion excluding the portion exceeding the threshold level L is shown.

Further, the area M4 includes M and M corresponding to B and G, respectively.
The MTF curve 37 corresponding to R in the portion where both the TF curves 373 and 372 exceed the MTF threshold level L
1 indicates a range of a portion excluding a portion exceeding the MTF threshold level L. The region M5 includes an MTF curve 373 corresponding to B or R in a portion where the MTF curve 372 corresponding to G exceeds the MTF threshold level L.
Or, 371 indicates a range of a portion excluding a portion exceeding the MTF threshold level L. Region M6 is MT
In the portion exceeding the F threshold level L, R,
M of MTF curves 371 to 373 corresponding to each color of G and B
The range of the portion where the portion exceeding the TF threshold level L does not exist is shown.

In this CCD main adjustment, the CTF is adjusted so that all of the MTF values corresponding to the pixel lines 1r, 1g, and 1b of each color exceed the preset MTF threshold level L.
Adjust the position of CD1 in the z-axis direction.

As shown in FIG. 10, z in step S15
In the subroutine of the axial CCD main adjustment process,
First, in step S19, an MTF common to each of R, G, and B colors is used.
Set the threshold level L.

Next, at step S20, each pixel line 1r, 1g, 1c of the CCD 1 at the adjustment start position of this step.
An MTF value corresponding to each of R, G, and B colors is obtained from the output of b. Next, in step S21, it is determined whether the MTF value of the R pixel line 1r exceeds the MTF threshold level L set in step S19. If the MTF value of the R pixel line 1r does not exceed the MTF threshold level L, the process proceeds to step S22.

In step S22, G pixel line 1g
Is determined to exceed the MTF threshold level L set in step S19. G
If the MTF value of the pixel line 1g does not exceed the MTF threshold level L, the process proceeds to step S23.

In step S23, the B pixel line 1b
Is determined to exceed the MTF threshold level L set in step S19. B
If the MTF value in the pixel line 1b does not exceed the MTF threshold level L, the process proceeds to step S24.

In step S24, after moving by a fixed amount in the z-axis direction, a search is made in the z-axis direction. Then, in the next step S32, based on the movement search in step S24,
The MTF is measured, and a range (region) M1 in which all the MTF values corresponding to each of the colors R, G, and B exceed the MTF threshold level L set in step S19 is determined.

Then, in step S33, step S
The block including the CCD1 is moved to the center of the area M1 determined in 32. In step S23, the pixel line 1b of B
Is greater than the MTF threshold level L set in step S19, the process proceeds to step S2.
Go to 5.

In step S25, the block including the CCD 1 is moved in the z-axis direction (direction moving away from the imaging lens 3) at an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 and the above-described step S32
And the process of step S33 is performed. G in step S22
If the MTF value of the pixel line 1g exceeds the MTF threshold level L set in step S19, the process proceeds to step S26. In this case, in this embodiment, as shown in FIG. 13, the MTF value of the B pixel line 1b also exceeds the MTF threshold level L.

In step S26, the block including the CCD 1 is moved in the z-axis direction (direction moving away from the imaging lens 3) at an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 and the above-described step S32
And the process of step S33 is performed. R in step S21
If the MTF value of the pixel line 1r exceeds the MTF threshold level L set in step S19, the process proceeds to step S27.

In step S27, G pixel line 1g
Is determined to exceed the MTF threshold level L set in step S19. G
If the MTF value of the pixel line 1g does not exceed the MTF threshold level L, the process proceeds to step S28. In this case, in this embodiment, as shown in FIG. 13, the MTF value of the B pixel line 1b does not exceed the MTF threshold level L.

In step S28, the block including the CCD 1 is moved in the z-axis + direction (direction approaching the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 to perform the processes of steps S32 and S33 described above.

If it is determined in step S27 that the MTF value of the G pixel line 1g exceeds the MTF threshold level L, the flow advances to step S29. In step S29, the MTF value of the B pixel line 1b is set in step S29.
It is determined whether or not the MTF threshold level L set at 19 is exceeded. MT in B pixel line 1b
If the F value does not exceed the MTF threshold level L, the process proceeds to step S30.

In step S30, a block including the CCD 1 is moved in the z-axis + direction (direction approaching the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched. Then, the process proceeds to step S32 to perform the processes of steps S32 and S33 described above. If the MTF value of the B pixel line 1b exceeds the MTF threshold level L set in step S19 in step S29, the process proceeds to step S31.

In step S31, after moving and searching in the negative direction of the z axis, a search is made to move in the positive direction of the z axis from the survey start position. Then, the process proceeds to step S32 and the above-described step S32
And the process of step S33 is performed. Step S3
The search for movement in the z-axis direction in 1 is performed until one boundary of the area M1 is determined in step S32, and after one boundary is determined, the movement search is performed in the z-axis + direction. As described above, the MTF value corresponding to each color is set to the preset M
By monitoring and determining whether or not the TF threshold level L has been exceeded, the moving direction of the block CCD can be determined.

In the above-described embodiment, the case where the coarse adjustment of the CCD 1 is omitted and the processing is performed when the output from the CCD 1 cannot be obtained. If it is obtained, the block including the CCD 1 is moved in the z-axis + direction (the direction approaching the imaging lens 3) at an arbitrary moving amount (fine pitch) in step S24 as in the embodiment of FIG. Search.

In the above embodiment, a value common to each of the R, G, and B colors is set as the MTF threshold level L. However, at step S19, a different MT value is set for each of R, G, and B.
F threshold levels L _R , L _G , and L _B are set, and the MTF threshold levels L _R ,
L _G, of L _B, step S21, S22, S23, S
27, the determination may be made using the MTF threshold level of the color corresponding to the color of the pixel line to be compared in S29. In this case, in step S32, when the area is determined, the area is determined to be an overlapping part exceeding the MTF threshold levels L _R , L _G , and L _B for each of the R, G, and B colors.
By setting different MTF threshold levels L _R , L _G , and L _B for each of R, G, and B in this manner, the wavelength (color)
The MTF threshold level L can be adjusted according to the difference in the sensitivity of the photoconductor due to the above. In the above embodiment, the block CC is set at the center of the area M1 in step S33.
Although D is moved, it does not have to be the center as long as it is within the area M1.

Next, the operation of the main CCD adjusting apparatus according to this embodiment will be described with reference to FIGS. FIG.
4 is a flowchart showing an outline of a control flow of the control unit of the present embodiment, and FIG.
It is a figure which shows the tendency of a TF curve. In FIG. 15, the horizontal direction is z.
The axial direction (the left direction indicates the z-axis + direction, that is, the direction approaching the imaging lens, and the right direction indicates the z-axis-direction, that is, the direction moving away from the imaging lens), and the vertical direction is the MTF value, and the B pixel line 1b MTF curve 473 corresponding to pixel line 1 of G
MTF curve 472 corresponding to g and pixel line 1r of R
Is shown as the MTF curve 471 corresponding to. further,
An MTF threshold level L which is a preset MTF set value is shown. The portions of the pixel lines 1r, 1g, and 1b of each color exceeding the MTF threshold level L are divided into regions M1, M2, M3, and M6 according to the degree of overlap of the MTF curves 471 to 473.

An area M1 indicates a range where all of the MTF curves 471 to 473 corresponding to the respective colors of R, G and B exceed the MTF threshold level L.
The region M2 includes MTF curves 471, 4 corresponding to R and G.
Numeral 72 indicates the range of the portion where the MTF threshold level L is exceeded, excluding the portion where the MTF curve 473 corresponding to B exceeds the MTF threshold level L. The region M3 is a region where the MTF curve 471 corresponding to R exceeds the MTF threshold level L
Or the MTF curve 473 or 472 corresponding to G
The range of the portion excluding the portion exceeding the threshold level L is shown.

The area M6 is where the MTF threshold level L of the MTF curves 471 to 473 corresponding to the respective colors of R, G, and B in the portion exceeding the MTF threshold level L.
Indicates the range of the portion where no portion exceeds.

In this CCD main adjustment, the CTFs are set so that all of the MTF values corresponding to the pixel lines 1r, 1g, and 1b of each color exceed the preset MTF threshold level L.
Adjust the position of CD1 in the z-axis direction.

As shown in FIG. 14, z in step S15
In the subroutine of the axial CCD main adjustment process,
First, in step S419, an MT common to each of R, G, and B colors is set.
Set the F threshold level L.

Next, in step S420, each pixel line 1r, 1g,
An MTF value corresponding to each of R, G, and B colors is obtained from the output of 1b. Next, in step S421, it is determined whether the MTF value of the R pixel line 1r exceeds the MTF threshold level L set in step S419. R
If the MTF value of the pixel line 1r does not exceed the MTF threshold level L, the process proceeds to step S422.

In the step S422, the G pixel line 1
g is the MT value set in step S419.
It is determined whether or not the F threshold level L has been exceeded. If the MTF value in the G pixel line 1g does not exceed the MTF threshold level L, step S4
Proceed to 23.

In step S423, the pixel line 1 for B
b is the MT value set in step S419.
It is determined whether or not the F threshold level L has been exceeded. If the MTF value in the B pixel line 1b does not exceed the MTF threshold level L, step S4
Proceed to 24.

In step S424, after moving by a fixed amount in the negative z-axis direction, a search is made to move in the positive z-axis direction. Then, in the next step S433, the MTF is measured based on the movement search in step S324, and the MTF corresponding to each of the R, G, and B colors is measured.
A range (region) M1 in which all of the TF values exceed the MTF threshold level L set in step S419 is determined.

In step S434, the block including the CCD 1 is moved to the center of the area M1 determined in step S433. If it is determined in step S423 that the MTF value of the B pixel line 1b exceeds the MTF threshold level L set in step S419, the process proceeds to step S425.

In step S425, the block including the CCD 1 is moved in the z-axis direction (the direction away from the imaging lens 3) by an arbitrary moving amount (fine pitch) and searched.
Then, the process proceeds to step S433 and proceeds to step S433 described above.
433 and the processing of step S434 are performed. Step S
If the MTF value of the G pixel line 1g exceeds the MTF threshold level L set in step S419 at 422, the process proceeds to step S426. In this case, in this embodiment, as shown in FIG. 15, the MTF value of the B pixel line 1b is also the MTF threshold level L.
Is over.

In step S426, after moving by a fixed amount in the negative z-axis direction, a search is made to move in the positive z-axis direction. In the next step S433, the MTF is measured based on the movement search in step S426, and the MTF corresponding to each of the R, G, and B colors is measured.
A range (region) M1 in which all of the TF values exceed the MTF threshold level L set in step S419 is determined. In step S421, M in the R pixel line 1r
If the TF value exceeds the MTF threshold level L set in step S419, the process proceeds to step S427.

In the step S427, the G pixel line 1
g is the MT value set in step S419.
It is determined whether or not the F threshold level L has been exceeded. If the MTF value in the G pixel line 1g does not exceed the MTF threshold level L, step S4
Proceed to 26.

In step S426, as described above,
After a certain amount of movement in the z-axis direction, a search is made in the z-axis direction. Then, the process proceeds to step S433 to perform the processes of steps S433 and S434 described above.

In step S427, the G pixel line 1g
If the MTF value at the time exceeds the MTF threshold level L, the process proceeds to step S430. Step S4
At 30, it is determined whether the MTF value of the B pixel line 1b exceeds the MTF threshold level L set at step S419. If the MTF value in the B pixel line 1b does not exceed the MTF threshold level L, the process proceeds to step S431.

In S431, after moving by a fixed amount in the z-axis direction, a search is made to move in the z-axis positive direction. Then, step S4
Go to step S433 and step S433
The process of 434 is performed. If the MTF value of the B pixel line 1b exceeds the MTF threshold level L set in step S419 in step S430, the process proceeds to step S432.

In step S432, after moving and searching in the negative direction of the z axis, moving and searching in the positive direction of the z axis is performed from the survey start position.
Then, the process proceeds to step S433 and proceeds to step S433 described above.
433 and the processing of step S434 are performed. Note that the movement search in the z-axis direction in step S432 is performed in the area M1.
Is performed until one boundary is determined in step S432. After the one boundary is determined, the moving search is performed in the z-axis + direction. As described above, the moving direction of the block CCD can be determined by monitoring and determining whether the MTF value corresponding to each color has exceeded the preset MTF threshold level L.

In the above embodiment, the case where the coarse adjustment of the CCD 1 is omitted and the processing is performed when the output from the CCD 1 cannot be obtained, but the coarse adjustment of the CCD 1 has already been completed and the output from the CCD 1 If it can be obtained, similarly to the embodiment of FIG. 5, in step S424, the block including the CCD 1 is moved in the z-axis + direction (the direction approaching the imaging lens 3) at every movement amount (fine pitch). Search.

In the above embodiment, a value common to each of the R, G, and B colors is set as the MTF threshold level L. However, in step S419, a different M is set for each of R, G, and B.
TF threshold level L _R, L _G, Set L _B, the set R, G, MTF threshold level L _R for each B, L _G, of L _B, step S421, S422,
The determination may be performed using the MTF threshold level of the color corresponding to the color of the pixel line to be compared in S423, S427, and S430. In this case, step S43
In step 3, when the area is determined, the area is determined to be an overlapping portion exceeding the MTF threshold levels L _R , L _G , and L _B for each of R, G, and B colors. Thus, different MTFs for each of R, G, and B
By setting the threshold levels L _R , L _G , and L _B , the MT according to the difference in the sensitivity of the photosensitive member depending on the wavelength (color) is determined.
The F threshold level L can be adjusted. Also,
In the above embodiment, the block CCD is moved to the center of the area M1 in step S434, but may not be the center if it is within the area M1.

As apparent from the above description, according to the first aspect of the present invention, an image forming lens for converting an object to be read into an optical image, and three color pixels of red, green and blue for photoelectrically converting the optical image. In a solid-state imaging device position adjustment device that adjusts a relative position in the optical axis direction with a solid-state imaging device having a line based on output information of the solid-state imaging device, MTF values measured respectively corresponding to pixel lines of three colors Is compared with a preset MTF set value, and the moving direction of the solid-state imaging device is determined based on the comparison result. Therefore, the adjustment time can be greatly reduced.

According to the second aspect of the present invention, there is provided an imaging lens for converting an object to be read into an optical image, and a solid-state imaging device having three color pixel lines of red, green and blue for photoelectrically converting the optical image. In the position adjustment device of the solid-state imaging device that adjusts the relative position of the solid-state imaging device with the optical axis direction based on the output information of the solid-state imaging device, the MTF values respectively corresponding to the three color pixel lines are preset. Since the MTF set values corresponding to the pixel lines of each color are compared with each other, the MTF threshold level can be adjusted according to the difference in the sensitivity of the photoconductor due to the wavelength (color), in addition to the above effects.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an outline of a control flow of a control unit including an embodiment.

FIG. 2 is a block diagram of a position adjustment device controlled by the control flow of FIG.

FIG. 3 is an exploded perspective view of the image reading apparatus whose position is adjusted.

FIG. 4 is a block diagram of a CCD main adjustment device according to an embodiment;

FIG. 5 is a flowchart illustrating an outline of a control flow of a control unit according to the embodiment.

FIG. 6 is a diagram showing a tendency of an MTF curve pattern 1 corresponding to each pixel line.

FIG. 7 is a schematic diagram of an apparatus that performs image reading using a solid-state imaging device.

FIG. 8 is an explanatory diagram showing a position adjustment direction of the solid-state imaging device in FIG. 7;

FIG. 9 is a diagram illustrating a relationship between a solid-state imaging device and a pixel line.

FIG. 10 is a flowchart illustrating an outline of a control flow of a control unit according to a modification of the present embodiment.

FIG. 11 is a flowchart illustrating an outline of a control flow of a control unit according to another embodiment.

FIG. 12 is a diagram showing a tendency of an MTF curve pattern 2 corresponding to each pixel line.

FIG. 13 is a diagram showing a tendency of an MTF curve pattern 3 corresponding to each pixel line.

FIG. 14 is a flowchart illustrating an outline of a control flow of a control unit according to another embodiment.

FIG. 15 is a diagram showing a tendency of an MTF curve pattern 4 corresponding to each pixel line.

FIG. 16 is a diagram showing, for each pattern of the MTF curve, determination of whether or not the MTF curve in each region exceeds a threshold level.

[Explanation of symbols]

 Reference Signs List 1 solid-state imaging device 1b pixel line 1g pixel line 1r pixel line 3 imaging lens 71 MTF curve 72 MTF curve 73 MTF curve 271 MTF curve 272 MTF curve 273 MTF curve 371 MTF curve 372 MTF curve 373 MTF curve 471 MTF curve 473 MTF curve L MTF threshold level

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI H04N 5/225 H04N 1/04 102 (58) Investigated field (Int.Cl. ⁷ , DB name) H04N 1/028 H04N 1 / 04-1/207

Claims (2)

(57) [Claims] 1. A relative position in an optical axis direction between an imaging lens for converting an object to be read into an optical image and a solid-state imaging device having three color pixel lines of red, green and blue for photoelectrically converting the optical image. Is adjusted based on the output information of the solid-state imaging device, and the MTF measured for each of the three color pixel lines is adjusted.
Comparing the value with a preset MTF set value, and, when all of the measured MTF values exceed the set values, directing the solid-state imaging device in a direction away from the imaging lens once. And then moving toward the imaging lens, and M measured corresponding to the red and green pixel lines, respectively.
When all the TF values exceed the set value and the MTF value measured corresponding to the blue pixel line is below the set value, the solid-state imaging device is moved toward the imaging lens. And if the MTF value measured for the red pixel line is above the set value and the MTF value measured for the green pixel line is below the set value, Moving the image sensor toward the imaging lens; and measuring the MTF value corresponding to the red pixel line below the set value and measuring the MTF value corresponding to the green pixel line.
Moving the solid-state imaging device in a direction away from the imaging lens when the TF value exceeds the set value; and measuring the M measured corresponding to the red and green pixel lines, respectively.
When the TF value is less than the set value and the MTF value measured corresponding to the blue pixel line exceeds the set value, the solid-state imaging device is moved away from the imaging lens. Moving the solid-state image sensor once in a direction away from the imaging lens when the MTF values respectively measured for the red, green and blue pixel lines are all below the set values. Moving the solid-state imaging device toward the imaging lens after moving the solid-state imaging device. 2. A relative position in an optical axis direction between an imaging lens for converting a reading object into an optical image and a solid-state image sensor having three color pixel lines of red, green and blue for photoelectrically converting the optical image. Is adjusted based on the output information of the solid-state imaging device, and the MTF measured for each of the three color pixel lines is adjusted.
The value and M corresponding to the preset pixel line of each color
Comparing the TF setting value with each other, and when the measured MTF value of each color exceeds the corresponding setting value, the solid-state imaging device is temporarily moved in a direction away from the imaging lens, and thereafter, Moving toward the imaging lens, and measuring M corresponding to the red and green pixel lines, respectively.
When the TF value exceeds the corresponding set value and the MTF value measured corresponding to the blue pixel line is lower than the corresponding set value, the solid-state imaging device is turned toward the imaging lens. Moving and the MTF value measured for the red pixel line is above its corresponding set value and the MTF value measured for the green pixel line is below its corresponding set value. Moving the solid-state imaging device toward the imaging lens side, the MTF value measured corresponding to the red pixel line falls below the corresponding set value and corresponds to the green pixel line. Moving the solid-state image sensor in a direction away from the imaging lens when the measured MTF value exceeds the corresponding set value, and measuring the MTF value corresponding to the red and green pixel lines, respectively. M
When the TF value is lower than the corresponding set value and the MTF value measured corresponding to the blue pixel line exceeds the corresponding set value, the solid-state imaging device is moved away from the imaging lens. Moving the solid-state imaging device in a direction to temporarily move away from the imaging lens when the MTF values measured corresponding to the red, green, and blue pixel lines are respectively lower than the corresponding set values. And moving the solid-state imaging device toward the imaging lens after moving toward the imaging lens.